Four men were shot—three of them killed—in Northwest Baltimore on January 19, Report informs referring to CBS News.

One person is being treated for non-life-threatening injuries at a local hospital, according to authorities. The quadruple shooting took place near the 5200 block of Fairlawn Avenue just after 8 p.m.

That person showed up at the hospital after the shooting, according to Baltimore Police Commissioner Richard Worley.

The gunfire likely first erupted inside a business before the violence spilled outside of it, he said. He did not specify what type of business was involved in the shooting, noting that the investigation into the triple murder had just begun.

Worley also said he did not know if the victims were all colleagues.

Officers tried to render aid to the three who had fatal injuries but were able to revive them. One deceased person remains inside a building and the other two others are outside of the building, Worley said.